This study has two major aims: The first is to evaluate the efficacy of TL, in comparison with placebo TL (Sham lavage)(SL) in relieving joint pain in patients with knee OA. As we will allow subjects to continue their usual arthritis therapy which may or may not include an NSAID, we hope to define the potency of TL and to assess it both as an adjunct to, and as an alternative for, NSAID therapy. All study subjects will meet American College of Rheumatology criteria for knee OA and have current knee pain. Subjects with a broad spectrum of OA severity, as judged by knee radiography, will be included. We will employ 2 treatment groups of approximately 120 patients each. One group will undergo TL, while the other group will undergo sham lavage. To meet our second major aim, which is to determine whether the duration of response to TL is clinically significant, we will follow subjects at 12-week intervals for 6 months, and again after one year, during which time differences between treatment groups will be examined. A third, but lesser, objective is to identify clinical, radiographic, laboratory, socioeconomic and/or general health status factors that might predict responsiveness to TL.